DETROIT (Reuters) – Federal prosecutors on Friday recommended a three-year prison sentence for Volkswagen AG (DE) engineer James Liang for his role in a diesel emissions scandal that has cost the German automaker as much as $25 billion.

Liang, who pled guilty to misleading regulators, is cooperating with prosecutors and will be sentenced on Aug. 25.

Prosecutors in U.S. District Court in Detroit said Liang, a diesel engine expert with more than 30 years of experience at VW, “provided an insider’s perspective of a company that had lost its ethical moorings in pursuit of increased market share and corporate profits.”

The 62-year-old engineer from Newbury Park, Calif., appeared in U.S. District Court in Detroit on Friday and entered into a plea agreement that includes his cooperation with the government in its investigation. The indictment says Liang conspired with current and former VW employees to mislead U.S. regulators about the software that allowed the automaker to evade American emissions standards.

VW has already agreed to spend up to $16.5 billion to address environmental, state, and owner claims in the United States.

Liang was indicted in June, but the indictment was only made public on Friday.

Detroit — A veteran Volkswagen AG engineer’s guilty plea to a criminal charge Friday for his role in the automaker’s diesel emissions scandal has uncovered new revelations of a decade of deceit and coverups.

Federal documents unsealed Friday detail how VW engineers from the very beginning of the automaker’s so-called “clean diesel” program intentionally developed and installed a “defeat device” on roughly 500,000 cars from 2009 through 2015 in the United States so that they could appear to pass U.S. emissions tests.

The details were made public as James Robert Liang, leader of diesel competence for VW from 2008 through June, appeared in U.S. District Court in Detroit. He entered a guilty plea to a grand jury indictment of conspiracy to defraud the U.S. government, to commit wire fraud and to violate the Clean Air Act. The maximum penalty is five years in prison and a $250,000 fine.

It marks the first criminal charge in the year-long scandal at the German automaker and could indicate more charges against VW officials are coming in the Department of Justice investigation into the company.

The 10-year conspiracy unfolded in 2015 and is expected to cost the automaker billions. The company admitted to lying on emissions tests for roughly 11 million diesel vehicles worldwide, including about 500,000 in the United States. VW has already agreed to pay $16.5 billion to consumers and dealers as a result of the scandal. It continues to face a civil Justice Department lawsuit in Detroit and a class-action lawsuit in California.

…“This is important because he’s admitting to a conspiracy, and of course you have to have someone else with you conspire,” said Peter Henning, a Wayne State University law professor and former federal prosecutor. “The interesting question is who in Germany can he identify and testify against.”

In a plea agreement with the government signed Aug. 31 by Liang, 62, of Newbury Park, Calif., prosecutors say in exchange for his agreement to cooperate with the government, it agrees not to use new information about Liang’s own criminal conduct against him at sentencing.
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Criminal conspiracy

In court Friday, Assistant U.S. Attorney Mark Chutkow said Liang knew two or more of his colleagues engaged in the same criminal acts, and that Liang emailed co-workers in the United States and Germany from 2012 to 2015 to further the conspiracy.

Liang and others, according to federal documents, at least twice attempted to cover up the existence of the defeat device.